This invention relates, in general, to voltage level detecting circuits, and more particularly, to a field effect transistor voltage level detector having a constant voltage reference.
Field effect transistors (FET) are finding wide use particularly in monolithic integrated circuits. It is often desirable to monitor power supply voltage changes on a monolithic integrated circuit particularly a microcomputer unit. Technology has advanced to a point to where a complete microprocessor along with a random access memory can all be integrated onto one silicon chip and it would be highly desirable to have an on-chip monitoring circuit for detecting the level of the power supply voltage. In the past, external logic and voltage comparators were used to monitor power supply voltage and to provide control signals for the monolithic integrated circuit having a minicomputer.
Accordingly, it is an object of the present invention to provide a constant voltage reference for a voltage level detector circuit.
Yet another object of the present invention is to provide an on-chip voltage level detector suitable for use on a monolithic integrated circuit having a microcomputer unit.